Motor fuel



Patented Nov. 23, 1937 UNITED STATES MOTOR FUEL Frank A. Howard, .Elizabeth, N. J., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application July 2, 1930, Serial No. 465,450. Renewed April 13, 1935 3 Claims.

The present invention relates to improved motor fuels, the nature of which and the method of manufacture of which will be fully understood from the following description.

There have been in the past many attempts to utilize kerosene effectively in internal combustion engines of the type operating on the Otto cycle or its commercial adaptations as distinguished from the Diesel engines to which this application has no reference. These attempts have not met with commercial success. One reason for failure has been the tendency for such high boiling oils to cause knocking in the engine. For efficient operation the compression pressure a should be as high as possible, but for ordinary kerosene the fuel knock becomes noticeable at pressure above about 50 pounds per square inch'. It will therefore be seen that such fuels cannot be used with any great success.

There have also been attempts to modify the kerosene by addition of easing head gasoline, benzol and the like or by addition of anti-detonating compounds such as tetraethyl lead, iron carbonyl and the like. These are also only successful to a slight degree. The addition of low boiling fractions in large quantities makes the fuel excessively volatile, and besides the hazard involved, it is difiicult to keep in a uniform condition. The addition of anti-detonants is also not completely successful as will be noted below, due to the excessively heavy ends boiling above 550 F.

In my experiments I have found that the most satisfactory fuel is a narrow boiling cut or fraction containing neither the excessively low boiling fractions characteristic of present fuels nor on the other hand the excessively high boiling components in kerosene. For my purposes the best out lies within the boiling range of 275 to 500 F. and preferably has a boiling range of not more than 158, 125 or 100 F. that is to say, boiling from about 275 to 400 F. or 350 to 425 F. or 350 to 475 F. The best boiling range for aeroplane fuels is from about 300 to 400 F. or 325 to 425 F. with a flash point above say 100 or 115 F. Such fuels start easily at engine temperature of say to or F. and possess many advantages not shown by the wide cut oils of higher or lower boiling range.

The hydroformed oils are prepared by subjecting a gas oil, kerosene or other heavy oil to the action of hydrogen under pressure in excess of 50 atmospheres to temperature above 900 or 950 F. for a limited time. Preferably, temperature is about 950 to 1000 F. and pressure about or 200 atmospheres, the oil pressure amounting to about and the hydrogen of the total. The oil is fed at a rate equivalent to about two volumes of oil per volume of reaction space per hour. The reactor is preferably filled with a suitable catalyst for eifecting the conversion. Preferred catalysts are those resistant to poisoning by sulphur, and as examples of these the oxides or sulphides of metals of the 6th group of the periodic system may be mentioned. These may be used singly or in mixtures with each other or other materials such as magnesialime, rare earths, alumina, thoria and the like.

. As an example of the nature and characteristics of my present fuels a hydroformed gas oil was distilled and cut to the following fractions, 1

and each was run in an engine to determine its anti-detonating characteristics, which are also noted:

Benzol T equi valen't Percent 43 46 48 Over 50 I ll IIT IV The benzol equivalent in the above table is the percent of pure benzol in admixture with an uncracked naphtha from ordinary sweet crude Gravity 28.5 A.P.I.

Sulfur 0.010% Abel flash 107 F. Color 28 Color hold-after 1 hr. sunlight 28 Air jet gum 4.8 Breakdown 0 lbs/4 hrs. Corrosion Passes Octane No. 300 F 98.0 Octane No. 375 F 87.5

Aniline point 24 F.

iii

Initial 309F. 10% 333 20% 339 30% 343 348 353 359 365 371 380 Final 411 Recovery 98.5

As a further description of my "fuels it will be observed that they are ordinarily water white in color, although they may have a slight yellowish tinge. Ordinarily sulphur is low, especially when hydroformed oils are used. Gum content is usual- 1y below 25 mg. per c. c. and always below such quantity as would give difficulty in an engine. The flash point is, as noted above, considerably above that of ordinary gasoline, which makes them especially suitable for aeroplane fuel, where fire hazard is to be avoided insofar as possible.

They are distinguished from the majority of fuels now on the market by absence of low boiling fractions and in having flash points above 100 F., and they are capable of producing greater power and efficiency in combustion. They are also distinguished from the heavy kerosene blends by the fact that they do not contain high boiling fractions above say 500 or 550 F. They are therefore characterized by close boiling range and anti-detonation properties, equivalent to sweet uncracked naphtha conforming to current U. S. specifications for motor fuel from Mid-Continent crude petroleum to which from '30 to 60% or more of benzol has been added, this percentage being figured on the blend.

By the term inherent in the following claims referring to anti-detonation properties it is to be understood to mean that the anti-detonation quality is present in virtue of the hydrocarbons themselves. Naturally, such inherent anti detonation properties can be fortified or increased by addition of lead tetraethyl or iron carbonyl or other agents, if desired.

The present invention is not to be limited by any theory of the mechanism of the improved results shown by the oils or by the process for manufacturing them, nor by any particular example of distillate range or the like, but only by the following claims in which I wish to claim all novelty inherent in my invention.

I claim:

1. An improved fuel for high compression engines, operating on the Otto cycle, comprising a hydroformed oil, having a flash point above 100 F., an end point below 500 F. and inherent auti-detonation properties at least equal to those of a sweet uncracked gasoline from Mid-Continent crude, to which 30% of pure benzol has been added, the percentage being figured on the gasoline-benzol blend.

2. An improved fuel for high compression engines, operating on the Otto cycle, comprising a hydroformed oil, having a flash point above 100 F., an end point below 450 F. and inherent antidetonation properties at least equal to those of a sweet uncracked gasoline from Mid-Continent crude, to which 40% of pure benzol has been added, the percentage being figured on the gasoline-benzol blend.

3. An improved fuel for high compression engines, operating on the Otto cycle, comprising a hydroformed oil, having a flash point above 100 F., an end point below 400 F. and inherent antidetonation properties at least equal to those of a sweet uncracked gasoline from Mid-Continent crude, to which 50% of pure benzol has been added, the percentage being figured on the gasoline-benzol blend.

' FRANK A. HOWARD. 

